The Ga vacancy mediated microstructure evolution of (Ga,Mn)As during growth and post-growth annealing was studied using a multi-scale approach. The migration barriers for the Ga vacancies and substitutional Mn, together with their interactions, were calculated using first principles. Temporal evolution at 200 to 350C was studied using lattice kinetic Monte Carlo simulations. It was shown that, at typical growth and annealing temperatures, Ga vacancies provided efficient diffusion transport for Mn and that, in 10 to 20h, the diffusion of Mn promoted the formation of clusters. Clustering reduced the Curie temperature and explained its decrease during long-term annealing.

Diffusion and Clustering of Substitutional Mn in (Ga,Mn)As. H.Raebiger, M.Ganchenkova, J.Von Boehm: Applied Physics Letters, 2006, 89[1], 012505